This invention relates to a towing vehicle, and more particularly to a towing vehicle suitable for recovering disabled vehicles.
It is conventional on recovery vehicles intended for recovery of heavy commercial vehicles to provide means for lifting the front of a vehicle being towed. Such lifting means may be in the form of a crane, or an arm pivotally mounted on the recovery vehicle chassis and movable relative to the recovery vehicle chassis by means of hydraulic rams to lift the vehicle being towed.
It is a consequence of applying an upward lifting force to a vehicle being towed that a torque is applied to the towing vehicle, tending to rotate the towing vehicle about the rear axle assembly thereof. The effect of this torque is to reduce the loading on the front axle of the towing vehicle when the lifting force is applied. Unless satisfactory precautions are taken, this could lead to front axle loading which is inadequate to provide safe steering of the towing vehicle. The front axle loading cannot satisfactorily be increased by means of counter-balance weights located at the front of the vehicle since if such weights were permanently located the front axle loading would become excessive when the towing vehicle was not applying a lifting force to a towed vehicle. The use of removable counter-balance weights would clearly be impracticable.
The accepted solution to the above problem is to make the wheel-base of the towing vehicle sufficiently long to maintain satisfactory front axle loading when the maximum permissible lifting force is being applied by the lifting tackle. However, this arrangement leads to the disadvantage that the vehicle is excessively long, thereby greatly reducing the maneuverability of the vehicle.